Centrifugal casting



y 22, 1934. F. e. CARRINGTON ,959,

GENTRIFUGAL CASTING Filed Feb. 18, 1933 ATTORNEY Patented May 2 2, 1934 UNITED STATES PATENT oFnci-z 4 Claimsr (Cl. 22-79) This invention relates to improvements in machines for centrifugally casting metal, and has for its object improvements in the reservoir or ladle from which molten metal is poured into the mold feeding trough, and in the mechanism for actuating that ladle.

Centrifugal casting machines of the so-called de Lavaud or spout type are commonly provided with a tilting ladle pivotally mounted on a standard above and behind the pouring trough. During the casting operation this ladle is slowly tilted, discharging a continuous stream of molten inetal into an inclined runner from which it flows into the trough and thence into the receding rotating mold, the tilting of the ladle being synchronized with the mold traverse. Metal suflicient forone casting is supplied 'to the pouring ladle from a larger supply ladle which is carried from machine to machine usually by an overhead crane. In a plant in which a battery of casting machines are in operation, production may be slowed up by the inability of the supply ladle to make its rounds J speedily enough. 7

In order to overcome this difficulty I provide each machine with a pouring ladle of suiiicient size to hold enough metal to cast more than one pipe, usually two. Thus after one pipe has been cast another may be cast immediately thereafter without awaiting the return of the supply ladle. If, however, the pouring ladle is permitted to swing back under its own weight into its original position, as is the present practice, it becomes necessary to tilt it through half its total pouring are before the metal reaches the pouring lip for the second casting. As the ladle elevating mechanism is geared for a slow tilting motion synchronized with 'the mold traverse this means a loss of the time of one casting operation. If, on the other hand, the pouring ladle is tilted half way for the first pipe and then held in half-elevated position some of the metal will surge forward over the pouring lip and continue to trickle into the trough until the metal in the ladle comes to equilibrium. This metal trickling into the trough after the casting is complete freezes there and must be removed. before the next casting operation, otherwise it will be carried into the mold as solid particles and result in defective castings. In accordance with the present invention I provide means whereby when the power tilting the ing operation. The second tilting begins with the ladle only slightly. lowered from its position at the termination of the first casting.

In the accompanying drawing I have illustrated a preferred embodiment of my invention. In this drawing Figure 1 is a side elevation showing more or less diagrammatically a centrifugal pipe casting machine of the de Lavaud type and illustrating the improved ladle-tilting mechanism-of my invention; Figure 2 is a plan view, on an enlarged scale, of the ladle-tilting mechanism; Figure 3 is a vertical section taken along line 33 of Figure 2 and Figure 4 is an end view of the mechanism shown in Figures 2 and 3.

The centrifugal casting machine illustrated in Figure 1 comprises the usual mold 1 designed to be traversed longitudinally with reference tov a pouring trough 2. Mounted on a standard 3 above and to the left of the trough 2 is a tilting pouring ladle 4 which is tilted during casting to pour a stream of molten metal down runner 5 into the trough 2 and thence into the mold. The foregoing is a common construction and, of itself, forms no part of the present invention.

I shall now describe the mechanism for tilting the pouring ladle with particular reference to Figures 2-, 3 and 4. A vertical connecting rod 6 is pivotally connected at its upper end to the ladle 4 and at its lower end to a pivoted segment '7, so that as the segment 7 is swung about its pivot the ladle 4 is correspondingly swung about its pivot. The segment '1 is actuated by a motor 8 driving a pinion 9 meshing with teeth 11 on the periphery of the segment.

I shall now describe the mechanism for holding the ladle in elevated positionat the termination of the first casting operation. The segment 7 carries on one face a ratchet 12-which is engaged by a pawl 13 pivoted at one end of arm 14, pivoted at 15 and carrying counterweight 16, this counterweight urging the arm 14 into the position illustrated in Figure 3. During the upward or clockwise movement of the segment 7 the pawl 13 slides over the ratchet. Upon reversal of this movement, however, the pawl engages the adjacent ratchet tooth and holds the segment against return movement.- The arm 14, however,is free to swing through a small arc until it engages a stop 17.

In the casting of pipe centrifugally in the machine just described the ladle 4 is filled from the supply ladle with sufficient metal for, let up say. two pipes. The mold is retracted to cover the pouring trough and when everything is in readiness the motor switch is closed andthe segment 'l, acting through connecting rod 6, slowly tilts the ladle and the pipe is cast in the usual way.

.At the termination of the first casting operationthe ladle has been elevated only halfway and is still half filled with molten metal. At this pointangle between arm 14 and its stop 1'1. When the arm 14 engages stop 17, further downward move -ment is arrested. The parts will then remain in this position until the time comes for the secand casting whereupon the operator closes the motor switch and elevation of the ladle 4 is resumed.

At the termination of the second casting operation the ladle would also be held in an elevated position, so in order to return it for refilling I provide a plunger 18, mounted in a cylinder 19, which plunger is actuated to strike the pawl 13 disengaging it from the ratchet and permitting the ladle 4 and segment 7 to swing back under their own weight.

I claim: 4

-1. In a centrifugal casting machine, a pouring ladle capable of holding a charge of molten metal suflicient for a plurality of castings, means for tilting the ladle to discharge'the metal, a ratchet coupled to said ladle, a pawl engaging the ratchet and preventing return of the ladle when the tilting means cease to operate, and means whereby a slight downward movement of the pawl at the termination of the first casting operation is secured, thereby lowering the level of the residual metal but holding the ladle in. elevated position.

2. Ina centrifugal casting machine, a pouring ladle capable oi. holding a charge of molten metal suflicient for a plurality of castings, means for tilting the ladle to discharge the metal, a ratchet coupled to theladle, a pawl engaging the ratchet and preventing return of the ladle when the tilting means cease to operate, means whereby a slight downward movement of the pawl at the termination of the first casting operation is secured, thereby lowering the level of the residual metal but holding the ladle in elevated position and means for disengaging the pawl at the termination of a subsequent casting operation thereby permitting the ladle to return to its original position.

3. In a centrifugal casting machine, a pouring ladle capable of holding a charge of molten metal sufficient for a plurality of castings, means for tilting the ladle to discharge the metal, a ratchet coupled to the ladle, a pivoted counterweighted pawl engaging the ratchet and preventing return of the ladle when the tilting means cease to operate and a stop permitting a slight downward movement of the pawl at the termination of the first casting operation thereby lowering the level of the residual metal but holding the ladle in elevated position.

4. In a centrifugal casting machine, a pouring ladle capable of holding a charge of molten metal sufiicient for a plurality of castings, means for tiltingthe ladle to discharge the metal, a ratchet coupled to the ladle, a pawl engaging the ratchet and preventing return of the ladle .when the tilting means cease to operate, means whereby a slight downward movement. of the pawl at the termination of the first casting operation issecured thereby. lowering the level of the residual metal but holding the ladle in elevated position, and a plunger for disengaging the pawl at the -termination-of a subsequent casting operation thereby permitting the ladle to return to. its

original position.

4 FRANK G. CARRINGTON. 

